module Neo4j
  # == Keeps configuration for neo4j
  #
  # == Configurations keys
  class Config
    DEFAULT_FILE = File.expand_path(File.join(File.dirname(__FILE__), '..', '..', 'config', 'neo4j', 'config.yml'))
    CLASS_NAME_PROPERTY_KEY = 'class_name_property'

    class << self
      # In keeping with the Rails convention, this class writer lets you globally configure
      # the incluse of timestamps on your nodes and rels. It defaults to false, requiring manual
      # timestamp inclusion.
      # @return [Boolean] the true/false value specified.
      attr_writer :record_timestamps
      # @return [Fixnum] The location of the default configuration file.
      def default_file
        @default_file ||= DEFAULT_FILE
      end

      # Sets the location of the configuration YAML file and old deletes configurations.
      # @param [String] file_path represent the path to the file.
      def default_file=(file_path)
        delete_all
        @defaults = nil
        @default_file = File.expand_path(file_path)
      end

      # @return [Hash] the default file loaded by yaml
      def defaults
        require 'yaml'
        @defaults ||= ActiveSupport::HashWithIndifferentAccess.new(YAML.load_file(default_file))
      end

      # Reads from the default_file if configuration is not set already
      # @return [Hash] the configuration
      def configuration
        return @configuration if @configuration

        @configuration = ActiveSupport::HashWithIndifferentAccess.new
        @configuration.merge!(defaults)
        @configuration
      end

      # Yields the configuration
      #
      # @example
      #   Neo4j::Config.use do |config|
      #     config[:storage_path] = '/var/neo4j'
      #   end
      #
      # @return nil
      # @yield config
      # @yieldparam [Neo4j::Config] config - this configuration class
      def use
        @configuration ||= ActiveSupport::HashWithIndifferentAccess.new
        yield @configuration
        nil
      end

      # Sets the value of a config entry.
      #
      # @param [Symbol] key the key to set the parameter for
      # @param val the value of the parameter.
      def []=(key, val)
        configuration[key.to_s] = val
      end

      # @param [Symbol] key The key of the config entry value we want
      # @return the the value of a config entry
      def [](key)
        configuration[key.to_s]
      end

      # Remove the value of a config entry.
      #
      # @param [Symbol] key the key of the configuration entry to delete
      # @return The value of the removed entry.
      def delete(key)
        configuration.delete(key)
      end

      # Remove all configuration. This can be useful for testing purpose.
      #
      # @return nil
      def delete_all
        @configuration = nil
      end

      # @return [Hash] The config as a hash.
      def to_hash
        configuration.to_hash
      end

      # @return [String] The config as a YAML
      def to_yaml
        configuration.to_yaml
      end

      # @return [Boolean] The value of the config variable for including
      # timestamps on all models.
      def record_timestamps
        @record_timestamps ||= false
      end

      def class_name_property
        @_class_name_property = Neo4j::Config[CLASS_NAME_PROPERTY_KEY] || :_classname
      end

      def include_root_in_json
        # we use ternary because a simple || will always evaluate true
        Neo4j::Config[:include_root_in_json].nil? ? true : Neo4j::Config[:include_root_in_json]
      end

      def module_handling
        Neo4j::Config[:module_handling] || :none
      end

      # @return [Class] The configured timestamps type (e.g. Integer) or the default DateTime.
      def timestamp_type
        Neo4j::Config[:timestamp_type] || DateTime
      end

      def association_model_namespace
        Neo4j::Config[:association_model_namespace] || nil
      end

      def association_model_namespace_string
        namespace = Neo4j::Config[:association_model_namespace]
        return nil if namespace.nil?
        "::#{namespace}"
      end
    end
  end
end